Moscovian Conodonts from the Nevandi River Valley (Cantabrian Zone, North Spain)

Home , Cavusgnathus, Declinognathodus, Idiognathoides, Neogondolella, Polygnathus

Trabajos de Geología, Universidad de Oviedo, 32: 63-75 (2012)

Moscovian conodonts from the Nevandi River Valley (Cantabrian Zone, North Spain)

C. A. MÉNDEZ

Departamento de Geología, Universidad de Oviedo, C/Jesús Arias de Velasco s/n, 33005 Oviedo, Asturias, España. E-mail: [email protected]

Abstract: Taxonomic and biostratigraphic data concerning Moscovian conodont faunas are reported from a section in the Nevandi River Valley (North Spain). Idiognathodus and Idiognathoides are the dominant genera. Other genera recorded in the section are Declinognathodus, Gondolella, Neogondolella and Neognathodus. Many of the investigated conodonts are integrated by cosmopolitan species but two new taxa belonging to the genus Idiognathodus I. espinamaensis and I. mendezi are erected. The conodonts coming from the lower part and the upper part of the section are assigned to the lower Moscovian and upper Moscovian respectively.

Keywords: conodonts, Moscovian, Carboniferous, Cantabrian Zone.

Resumen: Se dan a conocer datos taxonómicos y biostratigráficos de conodontos moscovienses de una sección del Valle del Río Nevandi (norte de España). La mayor parte de dichos fósiles son elementos P1 con Idiognathodus e Idiognathoides como géneros dominantes. Otros géneros registrados son Declinog- nathodus, Gondolella, Neogondolella y Neognathodus. Muchos de los elementos investigados están inte- grados por especies cosmopolitas pero se crean dos nuevos taxones pertenecientes al género Idiogna- thodus: I. espinamaensis e I. mendezi. Los conodontos encontrados en la parte inferior y superior de la sucesión se asignan al Moscoviense inferior y superior respectivamente.

Palabras clave: conodontos, Moscoviense, Carbonífero, Zona Cantábrica.

The Picos de Europa Unit is located in the eastern part The Nevandi River Valley Section is located in the of the Cantabrian Zone (Julivert, 1971; Pérez Estaún South of the Picos de Europa Unit (Fig. 1) and con- et al., 1988) (Fig. 1). This structural unit exhibits a sists of more than 800 m thickness of an entirely good Carboniferous succession comprising mainly ma- marine succession (Tournaisian-upper Moscovian in rine limestones. Conodonts have been investigated for age), predominantly calcareous with abundant years in the Carboniferous of the area providing im- dolomite at several levels. The section crops out portant biostratigraphic data mainly in Lower Missis- along the Nevandi River Valley (south of Puertos de sipian and early Upper Pennsylvanian (for instance, Aliva) in the Espinama Council territory within the Truyols et al., 1984; Méndez and Menéndez, 1985; western part of the Cantabria Region (N Spain) Blanco Ferrera et al., 2005; Méndez, 2006). (Fig. 2). 64 C. A. MÉNDEZ

Figure 1. Geological sketch map of the Cantabrian Zone showing the position of the Río Nevandi Section (after Julivert 1971 and Pérez Estaún et al. 1988).

Figure 2. Geological map of the sampled area (after Marquínez, 1978).

Fusulinoideans, recorded for most of the succession ex- and Ponga Unit in the Cantabrian Mountains and concept for its 171 lower meters, allowed Villa (1985) to sidered subdivisions in terms of the Russian scale in distinguish intervals of Bashkirian, lower Moscovian the Moscovian levels of the Nevandi River section. The and upper Moscovian age within the series. Moreover, conodont faunas provided some degree of precision in the cited author proposed a correlation of the Nevan- terms of age mainly in the Lower-Middle Mississippi- di section with another in the Picos de Europa Unit an (Méndez and Menéndez, 1985). MOSCOVIAN CONODONTS FROM THE NEVANDI RIVER (CANTABRIAN ZONE) 65

Figure 3. Conodont distribution along the Middle Pennsylvanian beds within the Nevandi River Valley Section.

Up to now, no descriptions have been made of the massive limestones topped by a few meters of dolo- Moscovian conodonts of this section. In this work, ma- stones. terial is illustrated and described, and two new species are erected. The conodont fauna and comments on the age of the succession The lowest 31 meters investigated correspond to the upper part of the Valdeteja Formation and consist of Most conodont specimens recovered are P1 elements, gray massive limestones. The rest of the succession be- generally well preserved, of the dominant genera Idiog- longs to the Picos de Europa Formation (Fig. 3). This nathodus and Idiognathoides. Other genera recorded in lithostratigraphic unit is a 305 m thick succession. It is the section are Declinognathodus, Gondolella, Neogondo- subdivided into a lower member, about 50 m thick, lella and Neognathodus. The investigated genera as a made of thin-bedded dark gray limestones with some whole are integrated by cosmopolitan species and other intervals of chert and an upper member made of gray forms that differ morphologically from those elsewhere. 66 C. A. MÉNDEZ

Two new species: Idiognathodus espinamaensis and I. Genus Declinognathodus Dunn, 1966 mendezi are described from the lower part of the sec- Type species Cavusgnathus nodulifera Ellison and tion (Fig. 3). Graves, 1941 Declinognathodus marginodosus (Grayson, 1984) At the moment, it is not possible to place the Bashkiri- Figs. 4f, 4g an – Moscovian boundary using the conodonts recovered in the section. The lowest conodont sample (S V.1981 Declinognathodus noduliferus noduliferus (Elli- 201) with I. sinuatus can be reported to the lowermost son and Graves); Méndez and Menéndez-Álvarez, fig. Moscovian according to the fusulinoideans found by 3: 2. Villa (1985) below, not far from the stratigraphic level where sample S 201 was collected. *± 1984 Idiognathoides marginodosus n. sp.; Grayson, Pl. 1, figs.3, 4, 9, 10, 11, 14, only; Pl.2, figs.8, 9, 17, only. The cosmopolitan species Declinognathodus marginodosus (Grayson) and Neognathodus atokaensis Grayson .1999 Declinognathodus marginodosus (Grayson, 1984); are recorded from the Vereyan in Russia and Ukraine Nemyrovska, p.54, Pl. 2, figs.2, 8, 11-12, 17. (Nemyrovska, 1999; Goreva and Alekseev in Makhli- na et al., 2001). .1990 Declinognathodus marginodosus; Grayson; Pl. 4, figs. 9, 13, only. The genus Idiognathoides disappeared at the lowest Desmoinesian in the United States (Barrick et al., .1990 Declinognathodus marginodosus (Grayson); Ne- 2004) and is not recovered above the Podoslkian Russ- mirovskaya, p.42, Pl. 1, figs. 5-11. ian substage in the Cantabrian Mountains. In this section the last record of the genus at the level of the sam- .2001 Declinognathodus marginodosus (Grayson); Mak- ple B 197 could indicate a Kashirian or a Podolskian hlina et al.; Pl.XIII, figs.21-25; Pl. XIV, figs. 6, 8, age at the maximum (Fig. 3). only.

It is noteworthy the position of Idiognathodus cf. I. ex- Material: 12 specimens in a variable state of preserva- pansus close to the top of the investigated succession. I. tion: DPO 41747 (sample B 191, Picos de Europa expansus is reported from uppermost Desmoinesian in Formation, bedded member); DPO 41748, DPO the Midcontinent (USA) (Barrick and Walsh, 1999). 14220 (sample B 192, Picos de Europa Formation, Recently, we have recovered this species from Myach- bedded member). kovian in the Cantabrian Mountains (Méndez, un- published). We suggest a Myachkovian (Russian sub- Description: Platform long and slender. The platform stage) age for the last metres of the investigated series consists of two parapets decorated with nodules or in this study (Fig. 3). short ridges. A through generally deep extends between the parapets. In some specimen the trough is crossed by It is no possible to consider detailed subdivisions in two ridges at the maximum at the end of it. The cari- terms of the Russian scale, but the conodonts coming na is very short, strong and generally nodular. This from the lower part and the upper part of the section structure begins at the end of the blade at the ventral are assigned to the lower Moscovian and upper termination of the platform, bends to the rostral para- Moscovian respectively (Fig. 3). pet and joins with it. A small structure made from a short ridge or a few nodes is placed at one side of the Systematic palaeontology carina at the ventral termination of the platform on the rostral parapet and in most of the specimens meet The material illustrated and described here is made of with the end of the carina on the parapet.

P1 elements and deposited in the Department of Geo- logy (Palaeontology) of the University of Oviedo Remarks: The position of a small structure made from (DPO). nodules or a short ridge at the ventral termination of MOSCOVIAN CONODONTS FROM THE NEVANDI RIVER (CANTABRIAN ZONE) 67

Figure 4. a-d. Idiognathoides sinuatus Harris and Hollingsworth, 1933, a, oral view, sinistral element. Picos de Europa Formation (bedded member), sample B 192 (DPO 41776); b, oral view, sinistral element. Picos de Europa Formation (bedded member), sample B 191 (DPO 41775); c, oral view, dextral element. Picos de Europa Formation (bedded member), sample S 202 (DPO 41777); d, oral view, dextral element. Picos de Europa Formation (bedded member), sample B 191 (DPO 41775). e, Idiognathoides postsulcatus Nemyrovska, 1999, oral view. Picos de Europa Formation (bedded member), sample B 194 (DPO 14225); f-g Declinognathodus marginodosus (Grayson, 1984), f, oral view. Picos de Europa Formation (bedded member), sample B 192 (DPO 14220); g, oral view. Picos de Europa Forma- tion (bedded member), sample B 192 (DPO 41748); h-i, Neognathodus atokaensis Grayson, 1984, h, oral view. Picos de Europa Forma- tion (bedded member), sample B 191 (DPO 41781); i, oral view. Picos de Europa Formation (bedded member), sample B 192 (DPO 41782). j, Gondolella laevis Kossenko and Kozitskaya, 1975, oral inclined view. Picos de Europa Formation (massive member), sample S 206 (DPO 126337). k-m Neogondolella clarki (Koike, 1967), k, oral view. Picos de Europa Formation (bedded member), sample S 202 (DPO 126343); l, aboral view (same specimen); m, oral view of a broken specimen. Picos de Europa Formation (bedded member), sample S 202 (DPO 41783). All illustrated specimens are P1 elements. Scale bar = 100 µ, except figs j, k and m = 10 µ. DPO is the repository number at the Department of Geology (Palaeontology), University of Oviedo, Spain. 68 C. A. MÉNDEZ the platform at one side of the carina allow us to assign Material: 13 specimens well preserved in general, one our material to Declinognathodus marginodosus (Grayson) of them the holotype: DPO 41749 (sample S 203, Pi- from the Pennsylvanian of the Arbuckle Mountains cos de Europa Formation, massive member) (Fig. 3); (southern Oklahoma, USA). Grayson (1984) erected the rest are paratypes from the same formation: DPO the species and placed it in the genus Idiognathoides 41753, DPO 41755-41758 (sample S 202, bedded Harris and Holligsworth but as other authors we think member); DPO 41750-41752, 41754 (sample S 203, that a part of the material assigned by the author to massive member); DPO 41759-41760 (sample B 194, that genus can be better placed in Declinognathodus bedded member); DPO 41761 (sample B 197, mas- Dunn because a very short, although distinguishable, sive member). carina exists and is bended (or declined) to one side. On the contrary Grayson (1984) minimized this mor- Locus typicus: Nevandi River Valley, western of the phology. Cantabria Region. Located on the western slope of the valley, between Invernales de Igüedri to the south and Genus Gondolella Stauffer and Plummer, 1932 Puertos de Aliva to the north (Fig. 2). The locality is in- Type species Gondolella elegantula Stauffer and Plum- side the Espinama Council territory. mer, 1932 Gondolella laevis Kossenko and Kozitskaya, 1975 Stratum typicum: Silicified, gray, bedded limestone Fig. 4j with crinoids, located in the upper part of the bedded (A synonymy list was provided by Méndez et al., member of the Picos de Europa Formation. 1998 for this species) Derivatio nominis: After Espinama, the place-name of Material: One specimen, deteriorated in his aboral part the council where the section is located. showing a portion of the keel only: DPO 126337 (sample S 206, lower part of the massive member of Diagnosis: A species of the genus Idiognathodus char- the Picos de Europa Formation). acterized by a rounded caudal lobe, field of transverse ridges on the platform flat, subtriangular, without any Description: In oral view, element with platform rela- depressed area and adcarenal ridges of the same length. tively wide, smooth, slightly concave with thin margins. Carina denticulated, extended along the centre Description: In oral view, platform long, significantly of the platform; denticles robust, confluent in their curved and sharply pointed. Rostral margin convex; base; one of them, apical denticle, is more high, more caudal margin moderately concave. Two lobes are de- robust situated near the dorsal termination of the plat- veloped on both sides of the platform near its ventral form and inclined to the outside of this structure, in end; caudal lobe arranged like a semi-circular pattern line with the rest of the denticles. with a variable number of nodes; rostral lobe elongated with a few nodes. Short, moderate carina. Adcarinal No microsculpture is observed. ridges well developed extended a short distance in the ventral direction of the unit; a trend to lateral devel- Remarks: The morphology of the element described opment is observed. Field of the transverse ridges on above shows similarities with the original material of the platform subtriangular with a moderate number of Gondolella laevis Kossenko and Kozitskaya (upper ridges, flat without any depressed area. Moscovian of the Donets Basin). The species was recorded from different levels in the Pennsylvanian Microornamentation of polygonal aspect was observed (Méndez et al., 1998). in a few specimens (Fig. 5d).

Genus Idiognathodus Gunell, 1931 Remarks: The morphology of the rostral lobe, length Type species Idiognathodus claviformis Gunnell, 1931 of the adcarinal ridges and platform outline are the Idiognathodus espinamaenis n. sp. main differences with Idiognathodus mendezi, n. sp. de- Figs. 5b, c, d, e scribed in this work. MOSCOVIAN CONODONTS FROM THE NEVANDI RIVER (CANTABRIAN ZONE) 69

Figure 5. a. Idiognathodus cf. I. expansus Stauffer and Plummer, 1932, oral view. Picos de Europa Formation (top of the massive member), sample B 200 (DPO 41773). b-e. Idiognathodus espinamaensis nov. sp., b, oral view, holotype. Picos de Europa Formation (massive member), sample S 203 (DPO 41749). c, oral view, paratype. Picos de Europa Formation (bedded member), sample S 202 (DPO 41753). d, detail of microornamentation on the caudal lobe of the same specimen. e, oral view, paratype. Picos de Europa Formation (massive member), sample B 197 (DPO 41761). f-h. Idiognathodus mendezi nov. sp. f, oral view, holotype. Picos de Europa Formation (bedded member), sample B 194 (DPO 41762). g, oral view, paratype. Picos de Europa Formation (bedded member), sample B 194 (DPO 41763). h, oral view, paratype. Picos de Europa Formation (bedded member), sample B 194 (DPO 41767). All illustrated specimens are P1 elements. Scale bar = 100 µ, except fig.d = 10 µ. DPO is the repository number at the Department of Geology (Palaeontology), Uni- versity of Oviedo, Spain. 70 C. A. MÉNDEZ

The specimens described can be compared to Idiog- platform or slightly further away with several nodes of nathodus incurvus Dunn 1966, from the Morrowan of moderate size; adcarinal ridges convex towards the ca- the southwestern of the United States. However, the rina; rostral adcarenal ridge ending near to the ventral surface of the field of the transverse ridges on the plat- end of the platform; caudal adcarenal ridge ending any form is flat in the Spanish material and no groove or further. Carina short. Field of the transverse ridges on concavity are observed like the specimens illustrated the platform subtriangular with a significant number by Dunn. In addition, two morphological characters of cross ridges. in I. espinamaensis are different from the American material: the carina is more short and the caudal lobe, Microornamentation of polygonal aspect was observed arranged like a semi-circular pattern. in a part of the material integrating this species.

Idiognathodus mendezi n. sp. Remarks: The morphology of the rostral lobe, unequal Figs. 5f, g, h length of the adcarinal ridges and asymmetry of the platform are the main differences with Idiognathodus Material: 11 well preserved specimens, one of them the espinamaensis, n. sp. described in this work. holotype: DPO 41762 (sample B 194, Picos de Eu- ropa Formation, bedded member) (Fig. 3); the rest are Idiognathodus mendezi shows similarity with one of the paratypes from the same formation and member: DPO specimens figured in Proctor (1991, fig. 16: 12) like I. 41763-41770 (sample B 194) and DPO 41771-41772 incurvus M1 from the Atokan of the Dimple Lime- (sample S 202). stone in the Marathon Basin, USA, mainly in the ex- tension of the adcarenal ridge and morphology of the Locus typicus: Nevandi River Valley, western of the rostral lobe but our form has the field of the transverse Cantabria Region. Located on the western slope of the ridges on the platform, triangular, lacks of the slight valley, between Invernales de Igüedri to the south and concavity on it and shows a more short carina. Puertos de Aliva to the north (Fig. 2). The locality is in- side the Espinama Council territory. Idiognathodus aljutovensis Alekseev, Barskov and Kononova, 1994 from the lower Moscovian of Cen- Stratum typicum: Dark gray bedded limestone near the tral Russia have a much more symmetric platform with top of the bedded member in the Picos de Europa For- the adcarinal ridges ending more close than in our new mation. species.

Derivatio nominis: After Méndez, the surname of my Idiognathodus cf. Idiognathodus expansus Stauffer and son Carlos Méndez Rodríguez. Plummer, 1932. Fig. 5a Diagnosis: A species of the genus Idiognathodus char- acterized by an asymmetric platform. The rostral lobe Material: 1 specimen: DPO 41773 (sample B 200, Pi- is located on a prominent shoulder close to the ventral cos de Europa Formation, top of the massive member). termination of the platform. Adcarenal ridges different in length: the caudal one is more long. Description: In oral view, platform wide, slightly curved, significantly convex in oral direction. Rostral Description: In oral view, platform asymmetric. Rostral margin moderately convex; caudal margin expanded margin strongly convex near ventral termination of the in its ventral part then straight. Two different lobes dis- platform, then straight; caudal margin straight for most played in the unit; caudal lobe close to the rhomboid its lenght, convex close to the ventral termination of shape, expanded away from platform in its ventral part the platform. Lobes very different; rostral lobe showing with several moderate nodes arranged in two rows; ros- a ridge with the form of an shoulder made from fused tral lobe elongated with a few moderate nodes. Ad- moderate nodes mainly in adult forms; caudal lobe carenal ridges convex to the carina extended some dis- elongated, ending at the ventral termination of the tance in the ventral direction of the unit. Carina short, MOSCOVIAN CONODONTS FROM THE NEVANDI RIVER (CANTABRIAN ZONE) 71 strong. Field of the transverse ridges on the platform include our specimen in Idiognathoides postsulcatus Ne- tongue-like with a few strong transverse ridges with- myrovska, 1999 from the lower Moscovian of the out defined inclination. Donets Basin, Ukraine.

Remarks: Stauffer and Plummer (1932) originally de- Idiognathoides sinuatus Harris and Hollingsworth, scribed and figured I. expansus from a locality (Miner- 1933 al Wells) of the latest Desmoinesian of Texas, USA. Figs. 4a, b, c, d The only specimen we have exhibits similarity with the morphology of one of the specie`s cotype re-illustrat- *1933 Idiognathoides sinuata n. sp.; Harris and Ho- ed by Barrick and Walsh (1999, fig. 2: 2) mainly re- llingsworth; p.201, Pl. 1, fig. 14. lated to the rostral lobe and the ventral length of the adcarinal ridges. The paucity of our material allows us .1933 Idiognathoides corrugata n. sp.; Harris and to left it in open nomenclature. Hollingsworth; p. 202, pl.1, figs. 7, 8a, b.

Genus Idiognathoides Harris and Hollingsworth, .1933 Idiognathoides attenuata n. sp.; Harris and Hol- 1933 ligsworth; p. 203, pl. 1, figs. 9a, b. Type species Idiognathoides sinuatua Harris and Hollingsworth, 1933 .1980 Idiognathoides sinuatus Harris and Hollings- Idiognathoides postsulcatus Nemyrovska, 1999 worth, 1933; Bender, Pl. 1, figs. 17-33. Fig. 4e V. 1981 Idiognathoides sulcatus sulcatus Higgins and V. 1981 Idiognathoides sinuatus Harris and Hollings- Bouckaert; Méndez and Menéndez-Álvarez, fig. 3: 7. worth; Méndez and Menéndez-Álvarez; fig. 3: 6.

± 1984 Idiognathoides marginodosus n. sp. Morphotype V. 1981 Idiognathoides attenuatus Harris and Hollings- C; Grayson, Pl.1, figs.16, 18, Pl.2, fig.19, only. worth; Méndez and Menéndez-Álvarez; fig. 3: 4.

± 1985 Idiognathoides sulcatus Higgins and Bouckaert, .1981 Idiognathoides sinuatus Harris and Hollingsworth; 1968; van den Boogaard and Bless, fig. 9: 7, only. Landing and Wardlaw, Pl. 2, figs. 8-21.

*1999 Idiognathoides postsulcatus n. sp.; Nemyrovska ± 1984 Idiognathoides sinuatus Harris and Hollings- p. 70, Pl.3, figs.9, 18. worth; Grayson, Pl. 4, figs., 13, 14, 19, 20, only.

Material: One well preserved specimen: DPO 14225 .1984 Idiognathoides corrugatus (Harris and Hollings- (sample B 194, Picos de Europa Formation, bedded worth); Grayson, Pl. 4, figs. 4, 10. member). .1985 Idiognathoides corrugatus-sinuatus (Harris and Description: In oral view, platform elongate, narrow Hollingsworth, 1933); Higgins, Plate 6.4, figs. 1, 2, 3, composed of two long parapets. The free blade joins to 5. the rostral parapet at its ventral end and the caudal parapet terminates as a free margin. Rostral parapet with a .1985 Idiognathoides sinuatus Harris and Hollingsworth, slight curvature; its ventral part is swollen and its dorsal 1933; van den Boogaard and Bless, fig. 9: 1-4. part is made from a few discrete nodes. Caudal parapet like the rostral one but with its ventral part more ± 1995 Idiognathoides sinuatus Harris and Hollings- swollen. The most dorsal nodes on the parapet tend to worth; Nemirovskaya and Alekseev, Pl. 1, fig. 16, only. join. Shallow narrow trough between the parapets. ± 1995 Idiognathoides corrugatus (Harris and Hollings- Remarks: The kind of swelling on the parapets, length worth); Nemirovskaya and Alekseev, Pl. 1, fig. 11, of the platform and the trough morphology allow us to only. 72 C. A. MÉNDEZ

.1999 Idiognathoides corrugatus (Harris and Hollings- of its ventral part as a free margin. Both parapets covered worth, 1933); Nemyrovska, Pl. 3, figs. 2-4, 21; Pl. 4, with numerous strong transverse ridges that cross the fig. 8. concavity in between of the parapets.

.1999 Idiognathoides sinuatus Harris and Hollings- Sinistral element: In oral view, platform long, pointly at worth, 1933; Nemyrovska, Pl.3, figs.3, 8, 10, 13. the end of its dorsal part with two parapets (rostral and caudal). A deep trough of variable length is extended in .2001 Idiognathoides sinuatus Harris et Hollingsworth, between of the parapets. A variable number of strong 1933; Alekseev and Goreva in Makhlina et al., Pl. XIII, transverse ridges cross the trough. The blade in the ven- figs.7-9; Pl. XIV, figs. 1-5. tral part of the element joins to the rostral parapet with a slight curvature. The parapet continues with a moderate .2001 Idiognathoides corrugatus Harris and Hollings- convex border; is narrow or more developed, expanded or worth; Kulagina et al.; Pl.9, figs. 2, 3; Pl. 10, figs. 5-7. vertical, with transverse ridges. Caudal parapet with a variable outline, expanded with transverse ridges. .2001 Idiognathoides sinuatus Harris and Hollingsworth; Kulagina et al., Pl. 9, fig.1, Pl. 10, figs. 3, 4. Microsculpture was observed in one of the specimens at 350 magnifications on the most ventral part of the .2003 Idiognathoides corrugatus Harris and Hollings- platform. worth, 1933; Wang and Qi, Pl.1, fig.22. Remarks: I. sinuatus displays variable morphology as de- .2003 Idiognathoides sinuatus Harris and Hollings- scribed above either in dextral and sinistral P1 elements worth, 1933; Wang and Qi, Pl. 1, fig. 22, Pl. 2, fig. 17. and this fact have been observed elsewhere as well.

Material: 34 specimens relatively well preserved: DPO Our concept of Idiognathoides sinuatus is coincidental 41774 (sample S 201, Valdeteja Formation, uppermost with that of Lane (1968) or Landing and Wardlaw part); DPO 41775 (sample B 191, Picos de Europa (1981), so we consider dextral and sinistral P1 as an Formation, bedded member); DPO 41776 (sample B asymmetrical pair. 192, Picos de Europa Formation, bedded member); DPO 41777 (sample S 202, Picos de Europa Forma- Genus Neognathodus Dunn, 1970 tion, bedded member); DPO 41778 (sample S 203, Type species: Polygnathus basleri Harris and Picos de Europa Formation, massive member); DPO Hollingsworth, 1933 41779, DPO 14224 (sample B 195, Picos de Europa Neognathodus atokaensis Grayson, 1984 Formation, massive member); DPO 41780 (sample B Figs. 4h, i 197, Picos de Europa Formation, massive member) + 1941 Gnathodus wapanuckensis (Harlton); Ellison Description: Dextral and sinistral elements show some and Graves, Pl.2, fig. 14, only. morphological differences; they integrate a parasym- metric pair and we describe them apart. + 1970 Neognathodus basleri (Harris and Hollings- worth); Dunn, p. 336, Pl. 64, fig. 14, only. Dextral element: In oral view, platform long, pointly at the end of its dorsal part with two parapets (rostral and + 1975 Neognathodus bothrops Merrill; Merrill, p. 69, fig.17: 65, only. caudal). A concavity more or less developed (in with and length) is present in between of the parapets although *± 1984 Neognathodus atokaensis n. sp.; Grayson, p. 52, some specimen can display a nearly flat dorsal part of the Pl. 1, fig. 8; Pl. 2, figs. 1, 5a, 5b, 10-12, 16, 21, 23, platform. The blade in the ventral part of the element Pl.3, figs. 1a, 1b, 7a, 7b, 11, 16, 18, 22. joins to the rostral parapet with a moderate curvature. This parapet continues with a convex border. Caudal ± 1987 Neognathodus atokaensis Grayson; Grayson, parapet with variable outline ending at the termination Merrill and Miller (eds). Pl.8, figs.30, 37, 40, only. MOSCOVIAN CONODONTS FROM THE NEVANDI RIVER (CANTABRIAN ZONE) 73

.1990 Neognathodus atokaensis; Grayson, Pl. 4, figs. Material: Seven specimens not equally preserved: DPO 14221, DPO 126343, DPO 41783 (sample S 202, Pi- 14-16. cos de Europa Formation, bedded member); DPO .1992 Neognathodus atokaensis Grayson; Sutherland 126342 (sample S 203, Picos de Europa Formation, and Grayson, Pl. 2, fig.15. massive member); DPO 41784 (sample B 197, Picos de Europa Formation, massive member). + 2001 Neognathodus atokaensis Grayson; Goreva and Alekseev, in Maklhina et al. Pl. XIII, figs. ?10, 11, ?12, Description: In oral view, platform of elements elongate, 13-15, Pl. XIV, figs. 20, 21, only. wide, depressed in the centre with both margins ap- proaching in the ventral part. Ventral end of platform .2009 Neognathodus atokaensis Grayson; Kulagina et acute; dorsal end rounded. Carina extended along the al. in, Puchkov et al. Pl. 8, fig. 4. centre of the unit with denticles not very high and robust ending in a more developed apical denticle, very Material: Three specimens relatively well preserved close to the dorsal termination of the platform; some- from the bedded member of the Picos de Europa For- times, a more reduced denticle is associated with the api- mation: DPO 41781 (sample B 191); DPO 41782 cal one, located at the dorsal end of the unit. (sample B 192). In aboral view, basal cavity close to the dorsal end, broad, Description: Platform wide, arrow-like, dorsally point- deep with a loop around it closed near the dorsal end and ed with two distinct parapets inclined to the carina opened on the reverse side where is united to a grooved which is placed in sub-central position. Carina strong keel. Grooved keel extended along the centre of the ab- and nodular, ends at the dorsal extreme of the unit or oral surface of the platform surrounded by a elongated is very close. Caudal parapet, long, with moderately area that is gradually narrowing and rising towards the convex margin, extending from the ventral termina- ventral end. Elongated area surrounding the keel meets tion of the platform to the dorsal extreme decorated the basal cavity so that all elements form a unit. with numerous strong, transverse ridges that appears to radiate from a same point. Rostral parapet wider in Micro-ornamentation of polygonal aspect can be ob- its ventral part where is strongly convex then is gradu- served in oral view on the caudal and rostral sides of ally reducing and finish near the dorsal end of the unit the platform and its rims, in most of the material (Figs. but do not fuse with it. This parapet may have differ- 4k, m.). In addition, some other features like holes are ent transverse ridges and at its most dorsal part have observed on the oral surface of the platform and on the small ridges or nothing. Caudal parapet joins with ca- aboral side of it as well (included the grooved keel and rina at moderately higher level than the rostral para- the basal cavity) (Fig. 4m.). The meaning of the cited pet. In the complete specimen the ventral termination features, observed in a limited number of specimens, of the platform bends downward to the aboral side. would require an additional amount of P1 elements of N. clarki Remarks: The shape of the platform and parapets, length of the carina and character of the most dorsal Remarks: The morphology of the P1 element of this portion of the rostral parapet allow us to include our species is comparable to that of the different Pennsyl- material in Neognathodus atokaensis Grayson from the vanian findings worldwide. Pennsylvanian of the Arbuckle Mountains (southern Oklahoma, USA). Acknowledgments

Genus Neogondolella Bender and Stoppel, 1965 This work has been supported by Spanish government Type species Gondolella mombergensis Tatge, 1956 funding through Project BTE 2006-0454. The author Neogondolella clarki (Koike, 1967) would like to thank Dr. Pérez-Huerta (University of Figs. 4k, l, m Alabama at Tuscaloosa) for his revision of the English (A synonymy list was provided by Méndez et al., language of the manuscript as well as the referees sug- 1998 for this species) gestions. 74 C. A. MÉNDEZ

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